Photonic circuits are useful as optical data links in applications such as, but not limited to, high performance computing (HPC), optical memory extension (OME), datacenters (DC), and device interconnects. For example, in mobile computing platforms a photonic IC (PIC) is a useful means of input/output (I/O) to rapidly update or sync a mobile device with a PLC device and/or cloud service where a wireless or electrical link has insufficient bandwidth. Such optical links utilize an optical I/O interface that includes an optical transmitter and an optical receiver.
PLCs entail an architecture in which at least the optical coupling of photonic components is provided, at least in part, by a planar substrate, such as a semiconductor wafer, that is fabricated in accordance with the many techniques employed in the manufacture of electrical integrated circuits (EICs).
In the current state of the art, a number of active electro-optical components, such as an emitting laser, and/or electro-absorption modulator (EAM) may be employed for an optical link. To date, these components remain relatively expensive as a function of their composition (e.g., employing III-V semiconductor substrates, complex epitaxial stacks, etc.), and further require precise alignment to the waveguide interconnecting them within the PLC. For example, where the lightwave circuit employs a single-mode planar waveguide, <1 μm (micron) accuracy is needed for sufficient optical coupling. Between the high average selling price of the active electro-optical components and the costs associated with active alignment equipment and performance of active alignment processes, high volume manufacturing of optical I/O links has yet to be attained. As a result, integration of such links into computing platforms remains prohibitively expensive.
Techniques and structures for integrating optical components onto a PLC substrate that reduce alignment costs and/or reduce component costs are therefore commercially advantageous.